PROBLEM TO BE SOLVED: To simply perform a priming process and eliminate the possibility of blood leakage in a transfusion treatment.SOLUTION: A blood purification apparatus 1 includes a blood purifier 10 purifying blood by making blood pass through a blood circuit 11 supplying the blood to the blood purifier 10 from a blood-collecting side end 11a and returns the blood having passed through the blood purifier 10 to a blood-returning side end 11b and a liquid introduction channel 12 to which the container 60 of a predetermined liquid can be connected and which introduces the liquid into the blood circuit 11 from the container 60. The blood circuit 11 is provided with a connector 30 with a valve, to/from which the liquid introduction channel 12 can be attached and detached, and the valve of which opens when the liquid introduction channel 12 is connected and closes when the liquid introduction channel is detached. The liquid introduction channel 12 is also attachable to and detachable from at least either the blood-collecting side end 11a or the blood-returning side end 11b of the blood circuit 11.
